Doppler processing is used in many radar applications to detect the presence of moving targets. Specifically, a signal is transmitted by the radar transmitter, the transmitted signal is reflected by a moving target, the reflected signal is received by the radar receiver, and the Doppler frequency shift due to the movement of the target is detected by the radar signal processor.
To enhance the performance of a radar, pulse compression signals can be used to increase range resolution. Pulse compression allows a long transmit pulse reflected from a target to be time compressed in the radar signal processor, thus increasing the range resolution of the radar.
A popular pulse compression radar signal is one that uses a pseudo-random noise (PN) code to bi-phase modulate the radio frequency carrier of the transmitter. The radar characteristics of this type of signal are well known to radar engineers skilled in the art.
Although the present invention can be applied to many pulse compression radar applications, this disclosure will describe its application to the radar intrusion detection system disclosed in U.S. Pat. No. 6,922,145 “Intrusion Detection, Tracking, and Identification Method and Apparatus”, which is incorporated herein by reference.